A Comparison Study of the Amplification Characteristics of the Seismic Observation Sites Using Coda Wave, Background Noise, and S-Wave Energy from Fukuoka Earthquakes Series

Abstract:

Since design response spectrum does not reflect local soil characteristics, site specific response spectrum from observed ground motions appears relatively higher than design response spectrum at high frequency range. These problems have been pointed out from the domestic seismic design industry. Among various estimation methods, this study used the method H/V ratio of ground motion for estimating site amplification. The method has been extended to background noise, Coda waves and S waves recently for estimating site amplification. This study applied the method to the 3 kinds of seismic energy simultansously, that is, background noise, Coda wave energy and S waves. This study analysed more than 267 background noises from 15 macro earthquakes including main Fukuoka earthquake (2005/03/20, M=6.5) and then compared results from background noise, Coda wave energy, and S waves, at the specific seismic station, for all the 8 main domestic seismic stations(KRA, GSU, GKP1, TJN, HKU, HSB, SNU, and KHD). The results showed that, at the specific sesimic station, most of the domestic seismic stations showed similar results among 3 different seismic energies. Each station showed its own characteristics of site amplification property in low, high and specific resonance frequency ranges. Comparison of this study to other studies using different method can give us much information about dynamic amplification of domestic sites characteristics and site classification.